Adverse Immune Reactions


Below is the introduction and summary to this article, the full article includes information about the types of hypersensitivity (types I-IV) you can view and download it now for free at www.jameswatts.co.uk

Introduction

The immune system has become adapted to ensure that ‘self’ cells are not subject to an immune attack. The body is able to do this because tolerance is developed towards self-cells, should this tolerance be broken down by some means, the host becomes subject to autoimmune attacks which can be potentially damaging.

Autoimmunity

Autoimmunity occurs when the body fails to recognise self-cells from non-self, this results in immune responses and damage to the tissue of the host. The variety of autoimmune responses can be split generally in to two groups; organ specific and non-organ specific. In autoimmune responses it is thought that either over reactive T-helper cells or deficient T suppressor cells are the cause. Autoimmunity can also be induced by reactions to a foreign antigen that then reacts with a self-antigen to invoke a response, for example infection with a minor bacteria (streptococcus) can lead to antibodies being produced against an antigen displayed on heart valves that would lead to cardiac problems. Autoimmunity is diagnosed by autoantibodies and the deliberate induction of autoimmunity has been used to control fertility and tumours (immunotherapy).

Summary

  • Autoimmunity – Inappropriate immune response to self antigens
  • Hypersensitivity – Overactive immune response to foreign and self antigens
  • Immunodeficiency – Ineffective immune response
  • Type I hypersensitivity – (IgE mediated, initiated in 2-30 minutes) Antigen induces cross-linking of IgE bound to mast cells with release of vasoactive mediators.
  • Type II hypersensitivity – (Antibody-mediated cytotoxic, 5-8 hours) Antibody directed against cell-surface antigens mediates cell destruction via ADCC or complement.
  • Type III hypersensitivity – (Immune complex mediated, 2-8 hours) Antigen-Antibody complexes deposited at various sites induces mast cell degranulation, neutrophil degranulation damages tissue.
  • Type IV hypersensitivity – (Delayed cell-mediated, 24-72 hours) Memory TH1 cells release cytokines that recruit and activate macrophages.
Advertisements
  1. Hrmm that was weird, my comment got eaten. Anyway I wanted to say that it’s nice to know that someone else also mentioned this as I had trouble finding the same info elsewhere. This was the first place that told me the answer. Thanks.

  1. No trackbacks yet.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: